Re: [Boost-users] math tools roots

Subject: Re: [Boost-users] math tools roots
From: Peter Dimov (pdimov_at_[hidden])
Date: 2011-10-10 05:55:12

Viatcheslav.Sysoltsev_at_[hidden] wrote:
> On Sun, 09 Oct 2011 19:04:39 +0200, Matwey V. Kornilov 
> <matwey.kornilov_at_[hidden]> wrote:
>
> > and, actually let a=b=x,
> >
> > lim_{x->0} ((x-x)/min(|x|,|x|)) = lim_{x->0} (0/min(|x|,|x|)) = 
> > lim_{x->0} (0) = 0
> >
>
> I'am not active mathematician, but I believe lim {x->0} (0/x) is 0/0 and 
> thus considered undefined, not 0.

lim 0/x is 0, but the original expression (with a and b) has no limit when 
a, b -> 0. If we let a = 2x, b = x, for example, we get lim(x->0) x/|x| 
which is either +1 or -1.